Camera computer apparatus

ABSTRACT

A computer for setting a camera for taking a photograph includes a photometer which is first adjusted in accordance with film speed. The photometer is then operable by aperture adjusting means for matching the illumination of a standard source with the illumination of an image to be photographed. After photometer adjustment, the aperture adjusting means is interrelated with a shutter speed control whereby either quantity may then be altered while maintaining a predetermined exposure value. When the aperture adjusting means is employed for operating the photometer, film speed adjustment is interengaged with the shutter speed control for maintaining an accurate relation between the various quantities.

United States Patent Saul 3,685,424 51 Aug. 22, 1972 154] CAMERACOMPUTER APPARATUS [72] Inventor: Ivar Saul, Portland, Oreg.

[73] Assignee: Tektronix, lnc., Beaverton, Oreg. [22] Filed: Aug. 4,1970 [21] Appl. No.: 60,788

[52] US. Cl. ..95/64 B, 95/10 B, 95/64 C [51] Int. Cl. ..G03b 9/02 [58]Field of Search ..95/64 B, 64 C, 10 B [56] References Cited UNITEDSTATES PATENTS 1,213,485 l/l917 Herz ..95/10B 2,509,385 5/1950 Ziaylek..95/64 C 2,912,914 11/1959 Weiss ..95/64 C 2,912,913 1l/1959 Bretthauer..95/64 C 2,874,622 2/1959 Gebele ..95/64 C X 2,829,574 4/1958 Gebele..95/64 C 2,596,328 5/1952 Dorsey ..95/64 C ll OBSERVERS EYE PrimaryExaminerSamuel S. Matthews Assistant Examiner-Monroe H. HayesAttorney-Buckhorn, Blore, Klarquist and Sparkman [5 7] ABSTRACT Acomputer for setting a camera for taking a photograph includes aphotometer which is first adjusted in accordance with film speed. Thephotometer is then operable by aperture adjusting means for matching theillumination of a standard source with the illumination of an image tobe photographed. After photometer adjustment, the aperture adjustingmeans is interrelated with a shutter speed control whereby eitherquantity may then be altered while maintaining a predetermined exposurevalue. When the aperture adjusting means is employed for-operating thephotometer, film speed adjustment is interengaged with the shutter speedcontrol for maintaining an accurate relation between the variousquantities.

SHUTTER mzm muczz r972 3.685.424

sum 1 or 2 I8 FIG.I V

I6 l2 20 I4 QB SERVERS I I 30 i EYE I 4 8 SHUTTER WAR 5 AU L INVENTORBUCKHORN, BLORE, KLARQUIST & SPARKMAN ATTORNEYS PATENTED M1822 1912SHEET 2 BF FIG. 3

I 68 a4 26 I am H H I v m; xmm p /50 ii j w I l rnnumunr 23 SHUTTER WARSAU L INVENTOR BUCKHORN, BLORE, KLARQUIST & SPARKMAN ATTORNEYSBACKGROUND OF THE INVENTION When taking a photograph of a usual scene,the only known quantity is the speed of the film. It is ordinarily up tothe operator to determine the scene brightness and accordingly set theaperture and shutter speed controls on the camera. An exposure meter orthe like may also be used to measure brightness of the scene. Thebrightness can be converted to aperture and shutter speed settings,taking the film speed into consideration, in accordance withcalculations made by the operator. Some automatic apparatus is availablebut generally interrelates only some of the quantities involved, whilerequiring the manual setting of one or more other values into the camerain accordance with calculation.

It is an object of the invention to provide improved apparatus forautomatically adjusting a camera wherein the various camera settings aresubstantially completely interrelated.

It is a further object of the present invention to provide an improvedanalog computer apparatus for a camera which apparatus is substantiallyfoolproof in operation while providing maximum operating flexibility.

It is a further object of the present invention to provide an improvedapparatus for automatically operating a camera associated with a cathoderay oscilloscope.

It is a further object of the present invention to provide an improvedmeans for interrelating all the various quantities which are ordinarilydetermined in exposing a film.

SUMMARY OF THE INVENTION According to the present invention, anadjustable photometer is employed for ascertaining the illumination ofan image to be photographed, for example, an electron beam trace on thescreen of a cathode ray oscilloscope. The photometer is initially set inaccordance with a film speed adjustment. Aperture adjusting means,including a variable iris for selecting a camera lens aperture, isalternatively interengageable with means for adjusting the photometer,or with means for establishing an interrelation between apertureadjustment and shutter speed. When aperture adjusting means is disposedin operative engagement with the photometer, a film speed selectingmeans is mechanically connected for simultaneous operation of shutterspeed adjusting means. However, when the aperture adjusting means andshutter speed adjusting means are mechanically interrelated, thephotometer is responsive to the film speed selecting means. In thismanner, the various quantities, which are ordinarily determined for filmexposure, are accurately and continuously interrelated in asubstantially foolproof manner for executing the usual exposureequation. The various quantities are not only mathematicallyascertained, but also the camera itself if functionally operated toexecute the various quantities determined.

The subject matter which I regard as my invention is particularlypointed out and distinctly claimed in the concluding portion of thisspecification. The invention, however, both as to organization andmethod of operation, together with further advantages and objectsthereof, may best be understood by reference to the followingdescription taken in connection with the accompanying drawings whereinlike reference characters refer to like elements.

DRAWINGS FIG. 1 is a schematic side view of camera apparatus accordingto the present invention as associated with the cathode ray tube of acathode ray oscilloscope;

FIG. 2 is a schematic illustration of computer apparatus according tothe present invention in a first or normal operating position;

FIG. 3 is a schematic illustration of computer apparatus according tothe present invention in a second operating position; and

FIG. 4 is a schematic illustration of a variable iris means employedaccording to the present invention.

DETAILED DESCRIPTION Referring to the drawings and particularly to FIG.1, a camera, generally indicated at 10, is positioned in front of thescreen of a cathode ray tube 12 and is employed for recording thevisible trace of an electron beam on the face of the tube. The camera isprovided with a computer 14 associated with a photometer including adichroic mirror 16 through which the image on the face of the cathoderay tube may be viewed via a hood 18. A light pipe 20 provides a spot oflight on the dichroic mirror 16, which is observed concurrently with anelectron beam trace. Then adjustments are made on the computer 14 formatching the illumination of such spot with the illumination of the beamtrace to be photographed. In accordance with the present invention,these adjustments automatically prepare the camera for photographing theimage.

The computer in accordance with the present invention is illustrated inFIGS. 2 and 3. The elements in the apparatus in each of these views aresubstantially identical, and only the operative position of themechanism is changed to illustrate operation of the device. Referring toFIGS. 2 and 3, an aperture adjusting means comprises a rotatable andslidable shaft 22 extending through panel 25 and upon which is mountedan aperture gear 24 and an operating knob 23. Gear 24 is keyed to theshaft and consequently moves in a longitudinal direction when the shaftis depressed as illustrated in FIG. 3, against the bias of spring 26.Gear 24 normally meshes with elongated gear 28 as well as with transfergear 30. Gear 28 turns cam operating gear 32 which supports and turnsiris cam 34, and is provided with a mechanical stop 29 for preventingmore than 360 rotation of gear 28. Iris cam 34 is contacted by camfollower 36 associated with variable iris mechanism 38, hereinafter morefully described, for

varying the lens aperture of the camera. It is noted that gear 24 is incontinuous meshing relation with gear 28 and consequently knob 23 willrotate gear 32 and cam 34 for operating the variable iris regardless ofwhether or not knob 23 is depressed toward panel 25.

Transfer gear 30, with which gear 24 meshes only in the FIG. 2 position,also engages shutter speed gear 40 as well as detent 42. Shutter speedgear 40 is attached to the shaft of shutter speed control 44 mounted onpanel 25 and having an operating knob 46 as well as a position detent48. Gear 40 is also provided with a stop for preventing more than 360rotation. The various switch positions of control 44 bring aboutdifferent shutter speeds. The camera shutter is desirably anelectromagnetically operated shutter as described and claimed in mycopending application, Ser. No. 845,354, filed July 28, 1969, now US.Pat. No. 3,595,153 and entitled Electrically Operated Shutter".

The apparatus is also provided with a film speed setting controlcomprising a shaft 50 carrying a front panel knob 52 for rotating longgear 54 mounted on shaft 50. Gear 54 is provided with a mechanical stop56 for preventing more than 360 rotation of the control.

In the position of the mechanism illustrated in FIG. 2, gear 54 engagesa gear 58 carried by a longitudinally slidable shaft 60. Shaft 60 isprovided with camming means 62 for engaging one end of a rocking arm 64,the opposite end of which is engaged by camming means 66 mounted onshaft 22. Rocking arm 64 is pivoted at 68 whereby, when knob 23 isdepressed towards panel 25, arm 64 rotates from the FIG. 2 position tothe FIG. 3 position against the bias of spring 26. Gear 58 carried onshaft 60 normally engages transfer gear 70, but

when knob 23 is depressed to the FIG. 3 position, gear 58 engagestransfer gear 30, as gear 24 engages gear 70 instead of gear 30. It isnoted that gear 58 continuously meshes with gear 54 mounted on shaft 50.

Large transfer gear 70 also engages a detent 72 as well as a smallergear 74 mounted on the same shaft 76 with gear 78. Gear 78, in turn,meshes with pinion 80 for rotating a first light attenuating filterwheel 82. Light attenuating filter wheel 82 has a gear sector forturning intermittent motion pinion 84 which, in turn, rotates lightattenuating filter wheel 86 on shaft 88. A color matching filter wheel90 is also mounted on shaft 88 for independent rotation with respectthereto. The filter wheels together with gears 70, 74, 78, 80 and 84form a part of the photometer means according to the present apparatus.

Also included in the photometer means is a standard light sourcecomprising lamp bulb 92 which emits light through filter sections 91, 87and 83 of light filter wheels 90, 86 and 82, respectively. Filtersections 87 and 83 are employed for variable light attenuating purposeswhereby, as filter wheels 82 and 86 rotate, a varying amount of lightfrom lamp bulb 92 will pass through these filters. Filter section 91, onthe other hand, is a color matching filter, suitably operated by athumbwheel, for matching the light color emitted from lamp bulb 92 withthe light color present at the cathode ray tube trace.

The photometer further comprises light pipe 20 (illustrated as broken inFIGS. 2 and 3 for ease of illustration) and dichroic mirror 16 alsoillustrated in FIG. 1. As was also illustrated in FIG. 1, the face orscreen of the cathode ray tube 12 is viewed through the dichroic mirrorat the same time as a light spot emitted from light pipe 20 is seen uponthe dichroic mirror. The light spot is, of course, produced by lightfrom lamp bulb 92 passing through the respective filters.

In FIG. 4 a shutter mechanism 94 is further illustrated and includesvariable iris mechanism 38 which is opened and closed by electromagnets96 and 98. The electromagnets 96 and 98 operate an armature or plunger100 to open the shutter for a predetermined time in accordance withselectable timing circuitry (not shown) associated with theelectromagnets. The plunger 100 opens and closes the rotatable actuatorarm 102 having a movable pivot 104 attached to rack 106. Rack 106 isgeared to rack 108 by way of pinion 110, and is moved back and forth bycam follower 36 against the bias of spring 112. As hereinbeforementioned, cam 34 operates cam follower 36. The shutter mechanism ismore fully described and claimed in my aforementioned application, Ser.No. 845,354. In general operation, the rotation of cam 34 moves pivot104 whereby to adjust the aperture provided by the iris mechanism 38when the shutter is opened.

Considering the operation of the system according to the presentinvention, and referring first to FIG. 2, gear 24 normally interconnectsgear 28 and transfer gear 30, the latter in turn rotating gear 40,whereby aperture adjustment and shutter speed adjustment are dependentupon one another. That is, rotation of knob 23 for decreasing the irisopening will normally increase the period of time the shutter will beopened, whereby to maintain an overall exposure value substantiallyconstant. Thus, rotation of either aperture knob 23 or shutter speedknob 46 will rotate the other for producing a substantially oppositeeffect in its numerical setting. At the same time, film speed knob 52 isoperatively connected to the photometer via gears 58, 70, 74, 78 and 80.It is noted gears 24 and 58 are wide enough so as to never be out ofcontact with one or the other of the transfer gears.

In the operation of the present invention, the film speed is normallythe initially known quantity and is consequently adjusted via knob 52,in accordance with a scale provided therefor on front panel 25, wherebyto adjust the photometer initially for film speed. At this time thephotometer is not used for matching the cathode ray tube trace with thespot of light provided on dichroic mirror 16 from light pipe 20.

Assuming the film speed is now set into the computer via knob 52, and animage is present on the face of cathode ray tube 12 which it is desiredto photograph, knob 23 is depressed to provide the interrelationshipillustrated in FIG. 3. Rotation of knob 23 will, of course, adjust theaperture opening by means of adjustable iris mechanism 38. However,speed control 44 will no longer be affected. Rotation of knob 23 will,at this time, rotate transfer gear and the remaining gear train of thephotometer. As knob 23 is rotated, filter wheels 82 and 86 are rotatedso as to vary the light provided by light pipe 20. The observer viewsthe cathode ray tube screen image through the dichroic mirror 16 withknob 23 depressed and rotates knob 23 until the spot of light providedby the photometer substantially matches the light intensity of the imageto be photographed. At the same time, gears 54 and 30 are interconnectedby gear 58 so that a change in either would have a corrective effect onthe other should either be changed.

After adjustment of the photometer by means of depressed aperture knob23, the aperture knob 23 is released so that gear 24 returns toengagement with transfer gear 30. At the same time, of course, gear 58returns to meshing engagement with transfer gear 70. As a result of theabove photometer adjustment, a setting of exposure value will be appliedto the aperture and shutter speed setting adjustments. With gears 28,

24 and 30 in interengagement, either knob 23 or 46 may be rotatedwithout upsetting this exposure value. Rotation of either knob 23 orknob 46 also rotates the other, and for any change in setting, the irisopening and the shutter speed will properly compensate for maintainingthe exposure value the same. Normally, after the aperture knob 23 hasreturned to the position illustrated in FIG. 2, the shutter speed knob46 will be adjusted to provide a shutter speed desired for theparticular event to be photographed. The aperture mechanism willautomatically follow the shutter speed selection in order to maintainexposure value constant.

The present apparatus operates according to the mathematicalrelationship A /T= 2 BS/K where A is the actual f-number of theaperture, T is the shutter speed in seconds, Ev is the exposure value, Bis illumination brightness as measured by the photometer, S is ASA filmspeed, and K is a constant. Expressed logarithmically, this relationshipreduces to the followmg:

Log A Log l/T= Log NS+ Log B/NK where N is another constant. If theaperture control is pushed in, then the mathematical relationship of thecontrol may be expressed as follows:

Log A Log B/NK= Log NS- Log UT 2 In the first of the two expressions,the basic relationship is given. At the time represented by thisequation, i.e. for the position of parts illustrated in FIG. 2, there isno interaction between the aperture-shutter gearing system and the filmspeed-photometer system. However, the basic equation will be obeyedsince the gearing is initially preset to maintain the equality. When theaperture knob is pushed in, the second of the two expressions applies sothat when the aperture knob is rotated, the amount of light attenuationof the comparison spot from light pipe 20 is changed until the spotmatches the cathode ray tube trace, whereby the exposure value ischanged. Now, if the aperture knob is allowed to come back to the FIG. 2position, the exposure computation is complete and the aperture andshutter speed knobs are then locked into a position related to a newtotal exposure value for matching the desired film speed and lightconditions. The various controls and panel scales are set up accordingto logarithmic values whereby to implement the above expressions.

Although computer operation is desired, it is obvious the variousquantities may also be altered for making fine adjustment, in case, forexample, the film speed is other than actually anticipated or ifphotometer comparison was improperly made. Aperture opening and shutterspeed may at any time be adjusted relative to one another by doing sowith the aperture knob 23 depressed.

While I have shown and described a preferred embodiment of my invention,it will be apparent to those skilled in the art that many changes andmodifications may be made without departing from my invention in itsbroader aspects. 1 therefore intend the appended claims to cover allsuch changes and modifications as fall within the true spirit and scopeof my invention.

lclaim:

l. A computer for a camera, comprising:

a first aperture-setting gear provided with gearing operativelyconnected thereto and a variable iris responsive to said gearing forvarying the lens aperture of said camera,

shutter speed adjusting means including a gear rotatable therewith,

gearing means for normally interrelating said aperture-setting gear andsaid shutter speed gear,

a variable photometer apparatus for comparing an image to bephotographed with a source, said photometer apparatus including lightattenuating filters provided with gearing for rotating said filters inthe path of light from said source with which an image to bephotographed may be compared,

film speed setting means including a gear normally coupled in operativerelation to the gearing of said photometer,

and means for simultaneously moving said aperturesetting gear intooperative relation with said photometer gearing while providing a gearedconnection between said film speed setting gear and said shutter speedgear in place of said coupling with said photometer.

2. A photographic exposure computing means comprising:

adjustable aperture means including manually actuated drive means foradjusting said aperture means;

adjustable shutter means including manually adjustable drive means foradjusting said shutter speed means;

adjustable film speed indicating means;

adjustable photometer means;

manually actuated means including first connecting means forinterconnecting said aperture means with said shutter speed means forsimultaneous adjustment by either of said drive means and secondconnecting means for interconnecting said film speed indicating meanswith said photometer means for adjustment of said photometer means bysaid film speed indicating means when said aperture means isinterconnected with said shutter speed means;

shifter means for simultaneously shifting said first and secondconnecting means to disconnect said aperture means and said shutterspeed means and interconnect said aperture means with said photometermeans and simultaneously disconnect said aperture means and said shutterspeed means and interconnect said shutterspeed means with said filmspeed indicating means.

. A computer for a camera, comprising:

a first aperture-setting gear provided with gearing operativelyconnected thereto and a variable iris responsive to said gearing forvarying the lens aperture of said camera;

shutter speed adjusting means including a gear rotatable therewith;

gearing means for normally interrelating said aperture-setting gear andsaid shutter speed gear;

a variable photometer apparatus for comparing an image to bephotographed with a source, said photometer apparatus including lightattenuating filters provided with gearing for rotating said filters inthe path of light from said source with which an image to bephotographed may be compared;

7 8 film speed setting means including a gear normally shaft on whichsaid aperture-setting gear is coupled in operative relation to thegearing of said mounted, and a second gear normally disposed inphotometer; interengaging relation between said film speed means forsimultaneously moving said aperturegear and said photometer gearing;

setting gear into operative relation with said Said second gear having ashaft also movable by said, photometer gearing while providinga gearedcon- TOCkmg arm for moving said second gear into nection between saidfilm speed setting gear and operatlve reilanon between said film p Semngsaid shutter speed gear in place of said coupling gear d Sald shutter pd gear Wher} 531d PF i h id photometer; ture-settlng gear 18 moved intooperative relation said simultaneous moving means comprising a 10 Saidphotometer gealmg rocking arm operatively connected for moving a

1. A computer for a camera, comprising: a first aperture-setting gearprovided with gearing operatively connected thereto and a variable irisresponsive to said gearing for varying the lens aperture of said camera;shutter speed adjusting means including a gear rotatable therewith;gearing means for normally interrelating said aperture-setting gear andsaid shutter speed gear; a variable photometer apparatus for comparingan image to be photographed with a source, said photometer apparatusincluding light attenuating filters provided with gearing for rotatingsaid filters in the path of light from said source with which an imageto be photographed may be compared; film speed setting means including agear normally coupled in operative relation to the gearing of saidphotometer; and means for simultaneously moving said aperture-settinggear into operative relation with said photometer gearing whileproviding a geared connection between said film speed setting gear andsaid shutter speed gear in place of said coupling with said photometer.2. A photographic exposure computing means comprising: adjustableaperture means including manually actuated drive means for adjustingsaid aperture means; adjustable shutter means including manuallyadjustable drive means for adjusting said shutter speed means;adjustable film speed indicating means; adjustable photometer means;manually actuated means including first connecting means forinterconnecting said aperture means with said shutter speed means forsimultaneous adjustment by either of said drive means and secondconnecting means for interconnecting said film speed indicating meanswith said photometer means for adjustment of said photometer means bysaid film speed indicating means when said aperture means isinterconnected with said shutter speed means; shifter means forsimultaneously shifting said first and second connecting means todisconnect said aperture means and said shutter speed means andinterconnect said aperture means with said photometer means andsimultaneously disconnect said aperture means and said shutter speedmeans and interconnect said shutter speed means with said film speedindicating means.
 3. A computer for a camera, comprising: a firstaperture-setting gear provided with gearing operatively connectedthereto and a variable iris responsive to said gearing for varying thelens aperture of said camera; shutter speed adjusting means including agear rotatable therewith; gearing means for normally interrelating saidaperture-setting gear and said shutter speed gear; a variable photometerapparatus for comparing an image to be photographed with a source, saidphotometer apparatus including light attenuating filters provided withgearing for rotating said filters in the path of light from said sourcewith which an image to be photographed may be compared; film speedsetting means including a gear normally coupled in operative relation tothe gearing of said photometer; means for simultaneously moving saidaperture-setting gear into operative relation with said photometergearing while providing a geared connection between said film speedsetting gear and said shutter speed gear in place of said coupling withsaid photometer; said simultaneous moving means comprising a rocking armoperatively connected for moving a shaft on which said aperture-settinggear is mounted, and a second gear normally disposed in interengagingrelation between said film speed gear and said photometer gearing; saidsecond gear having a shaft also movable by said rocking arm for movingsaid second gear into operative relation between said film speed settinggear and said shutter speed gear when said aperture-setting gear ismoved into operative relation with said photometer gearing.